Coordination between mac layer harq and rlc transmissions

Abstract

Method and apparatus for coordination between HARQ and RLC transmissions. A UE receives, from a network entity, an indication that a HARQ process has failed or terminated for a MAC layer. The UE initiates, at a RLC layer, a retransmission of RLC PDUs in response to receipt of the indication that the HARQ process has failed or terminated for the MAC layer.

What is claimed is: 
     
         1 . An apparatus for wireless communication at a user equipment (UE), comprising:
 at least one memory; and   at least one processor coupled to the at least one memory and, based at least in part on information stored in the at least one memory, the at least one processor is configured to:
 receive, from a network entity, an indication that a hybrid automatic repeat request (HARQ) process has failed or terminated for a medium access control (MAC) layer; and 
 initiate, at a radio link control (RLC) layer, a retransmission of RLC protocol data units (PDUs) in response to receipt of the indication that the HARQ process has failed or terminated for the MAC layer. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the at least one processor is configured to:
 inform, from the MAC layer, the RLC layer of reception of the indication that the HARQ process has failed or terminated, wherein the RLC layer initiates the retransmission of the RLC PDUs based on information from the MAC layer that the HARQ process has failed or terminated.   
     
     
         3 . The apparatus of  claim 1 , further comprising a transceiver coupled to the at least one processor, wherein the indication that the HARQ process has failed or terminated for the MAC layer is included in at least one of downlink control information (DCI) or medium access control (MAC) control element (CE) (MAC-CE). 
     
     
         4 . The apparatus of  claim 1 , wherein the indication includes an identifier (ID) of the HARQ process that has terminated. 
     
     
         5 . The apparatus of  claim 1 , wherein the at least one processor is further configured to:
 transmit an original set of RLC PDUs within a MAC PDU, wherein the indication indicates that the HARQ process has failed or terminated for the original set of RLC PDUs.   
     
     
         6 . The apparatus of  claim 1 , wherein reception of a scheduling downlink control information (DCI) that includes a toggled new data indicator (NDI) bit indicates that an initial transmission or the retransmission of the RLC PDUs was successfully received, and wherein the at least one processor is further configured to:
 discard the RLC PDUs included within a MAC PDU based on the reception of the DCI that includes the toggled NDI bit.   
     
     
         7 . The apparatus of  claim 1 , wherein the at least one processor is configured to:
 monitor for a scheduling downlink control information (DCI) that includes a new data indicator (NDI).   
     
     
         8 . A method of wireless communication at a user equipment (UE), comprising:
 receiving, from a network entity, an indication that a hybrid automatic repeat request (HARQ) process has failed or terminated at a medium access control (MAC) layer; and   initiating, at a radio link control (RLC) layer, a retransmission of RLC protocol data units (PDUs) in response to receipt of the indication that the HARQ process has failed for the MAC layer.   
     
     
         9 . The method of  claim 8 , further comprising:
 informing, from the MAC layer, the RLC layer of reception of the indication that the HARQ process has failed or terminated, wherein the RLC layer initiates the retransmission of the RLC PDUs based on information from the MAC layer that the HARQ process has failed or terminated.   
     
     
         10 . The method of  claim 8 , wherein the indication that the HARQ process has failed or terminated is received in at least one of downlink control information (DCI) or medium access control-control element (MAC-CE). 
     
     
         11 . The method of  claim 8 , wherein the indication includes an identifier (ID) of the HARQ process that has terminated. 
     
     
         12 . The method of  claim 8 , further comprising:
 transmitting an original set of RLC PDUs within a first MAC PDU, wherein the indication indicates that the HARQ process has failed or terminated for the original set of RLC PDUs.   
     
     
         13 . The method of  claim 12 , further comprising:
 monitoring for a scheduling downlink control information (DCI) that includes a new data indicator (NDI).   
     
     
         14 . The method of  claim 13 , wherein reception of the scheduling DCI that includes a toggled NDI bit indicates that an initial transmission or the retransmission of the RLC PDUs was successfully received, and wherein the method further includes:
 discarding the RLC PDUs included within a second MAC PDU based on the reception of the scheduling DCI that includes the NDI bit toggled.   
     
     
         15 . An apparatus for wireless communication at a network entity, comprising:
 at least one memory; and   at least one processor coupled to the at least one memory and, based at least in part on information stored in the at least one memory, the at least one processor is configured to:
 receive, from a user equipment (UE), one or more transmissions that include radio link control (RLC) protocol data units (PDUs); 
 transmit, to the UE, an indication that a hybrid automatic repeat request (HARQ) process for the one or more transmissions has failed or terminated for a medium access control (MAC) layer; and 
 receive a retransmission of at least one of the RLC PDUs initiated from a radio link control (RLC) layer in response to the indication that the HARQ process has failed or terminated for the MAC layer. 
   
     
     
         16 . The apparatus of  claim 15 , wherein the indication that the HARQ process has failed or terminated is included at least one of downlink control information (DCI) or medium access control-control element (MAC-CE). 
     
     
         17 . The apparatus of  claim 15 , wherein the indication includes an identifier (ID) of the HARQ process that has terminated for the MAC layer. 
     
     
         18 . The apparatus of  claim 15 , wherein the at least one processor is configured to:
 transmit a scheduling downlink control information (DCI) that includes a toggled new data indicator (NDI) bit that indicates that an additional HARQ process for the RLC PDUs is successful.   
     
     
         19 . The apparatus of  claim 15 , wherein the MAC layer of the network entity provides the indication that the HARQ process has failed or terminated. 
     
     
         20 . The apparatus of  claim 15 , further comprising a transceiver coupled to the at least one processor.